Does AdSense actually work?

I use AdSense on most of my websites. Normally I will use a module for AdSense, either in the left-hand column, header or bottom. However, I think it's always beneficial if you can integrate the AdSense into a blog post if possible. For the life of me, I have not been able to get the integrated AdSense to work. It says not to put sign code in, which I have done. However, no AdSense shows up on my blog, only the AdSense that is contained in the left-hand module, and that is nothing to do with the blog